TY - BOOK

T1 - “Determining the effects of drainage control structures on whitebait in lowland Hawke’s Bay waterways.”

AU - Halstead, Reece

PY - 2020/2/15

Y1 - 2020/2/15

N2 - Inanga (Galaxias maculatus), 1 of the 5 diadromous Galaxiidae species and the most common of the whitebaits. Despite their wide distribution across the Southern Hemisphere, they are considered a declining species. This study aims to determine whether drainage structures, like pumping stations, flood gates and culverts act as potential barriers to migrating inanga in lowland Hawke’s Bay waterways and to assess the inanga’s preferred habitat type. Six fyke nets were set above (upstream) and below (downstream) drainage structures across 15 waterways and left for 4 hours whilst habitat assessments were conducted. Nets were returned and caught species abundance and fork lengths were measured. Data collected showed pumping stations and flood gates act as complete barriers whereas culverts and bridge aprons allow either partial or complete passage upstream. Fewer inanga were caught in tidal sites with fluctuating water and salinity levels and in areas with little shade, high macrophyte cover and little bank vegetation. Fish passage remediations like fish ramps and fish friendly mechanisms require installation on culverts and flood gates to improve access for migrating fish upstream. Ecological remediations are required to provide suitable inanga habitat and subsequent increases in population numbers.

AB - Inanga (Galaxias maculatus), 1 of the 5 diadromous Galaxiidae species and the most common of the whitebaits. Despite their wide distribution across the Southern Hemisphere, they are considered a declining species. This study aims to determine whether drainage structures, like pumping stations, flood gates and culverts act as potential barriers to migrating inanga in lowland Hawke’s Bay waterways and to assess the inanga’s preferred habitat type. Six fyke nets were set above (upstream) and below (downstream) drainage structures across 15 waterways and left for 4 hours whilst habitat assessments were conducted. Nets were returned and caught species abundance and fork lengths were measured. Data collected showed pumping stations and flood gates act as complete barriers whereas culverts and bridge aprons allow either partial or complete passage upstream. Fewer inanga were caught in tidal sites with fluctuating water and salinity levels and in areas with little shade, high macrophyte cover and little bank vegetation. Fish passage remediations like fish ramps and fish friendly mechanisms require installation on culverts and flood gates to improve access for migrating fish upstream. Ecological remediations are required to provide suitable inanga habitat and subsequent increases in population numbers.

M3 - Commissioned report

BT - “Determining the effects of drainage control structures on whitebait in lowland Hawke’s Bay waterways.”

ER -